This application makes reference to, incorporates the same herein, and claims all benefits accruing under 35 U.S.C. xc2xa7119 from an application entitled Crossflow Fan for an Air Conditioner earlier filed in the Korean Industrial Property Office on Sep. 10, 1999, and there duly assigned Serial No.99-38647 by that Office.
1. Field of the Invention
The present invention relates to a cross flow fan, and more particularly to a cross flow fan of an air conditioner capable of reducing noise and vibration produced due to a rotation of the cross flow fan, by the improvement in an arrangement of blades on the cross flow fan.
2. Discussion of Related Art
Generally, a separate type air conditioner includes indoor and outdoor units connected with each other. The indoor unit includes an evaporator and a blower for circulating air. The blower sucks the inside air to pass the same through the evaporator, and discharges the heat-exchanged air back into the room. For the circulation of the indoor air, the blower is coupled with a driving source. i.e. a motor. The separate type air conditioner employs a cross flow fan as a blower for its indoor unit.
The cross flow fan may have multiple fan blades. The interval between the fan blades is called a fan pitch. In general, the cross flow fans have had considerable noise produced due to the rotation of the cross flow fan. Differing arrangements of the fan blades still produce high noise levels and vibration in the fan even at low frequencies (revolutions per unit of time of the cross flow fan).
An exemplar of the prior art Hamamoto et al. (U.S. Pat. No. 5,573,059, Air Conditioning Machine, Nov. 12, 1996) shows an air conditioning unit with a cross flow fan next to the heat exchanger. Kawabata et al. (U.S. Pat. No. 5,211,219, Air Conditioner, May 18, 1993) shows an air conditioner with a cross flow fan. Sugawara et al. (U.S. Pat. No. 4,462,750, Electric Fan Assembly, Jul. 31, 1984) discloses a cylindrical cross flow fan designed for use in a heating or cooling system. Chiguchi et al. (U.S. Pat. No. 5,924,923, Air Conditioner Indoor Unit, Jul. 20, 1999) discloses an indoor unit in a separate type air conditioner. Baker et al. (U.S. Pat. No. 5,588,484, Refrigeration Fan System, Dec. 31, 1996) discloses a fan system used in air conditioners or refrigerators. Shinobu et al. (U.S. Pat. No. 5,197,850, Cross Flow Fan System, Mar. 30, 1993) discloses a cross flow type fan having a tongue section.
I have found that none of the exemplar art discloses a cross flow fan that can reduce the noise and vibration produced due to the rotation of the cross flow fan.
The present invention has been made to overcome the above mentioned problems of the related art, and accordingly, it is an object of the present invention to provide a cross flow fan of an air conditioner capable of significantly reducing the noise produced due to a rotation of the cross flow fan, vibration produced due to an irregularity in the blade arrangement, and even the noise produced in the low frequency range of the cross flow fan.
It is another object to have a cross flow fan that can control a high volume of air without affecting the stability of an air conditioning system.
It is yet another object to have a cross flow fan that is optimally designed to be used in an indoor unit of a separate type air conditioning system.
It is another object to have a cross flow fan that has reduced noise at a high frequency.
In order to accomplish the above object, in a cross flow fan of an air conditioner installed in an indoor unit of the air conditioner and having a plurality of blades functioning to circulate an inside air according to the present invention, the multiple blades are divided into multiple blade groups of a uniform number of blades, however, angles between the two neighboring blades in the same blade group are gradually increased, and blade arrangements are consistent throughout all the blade groups.
In the cross flow fan of the air conditioner according to the present invention, the blade arrangement throughout the blade groups is regular, while the blade arrangement in each blade group is irregular. Accordingly, the noise caused due to the rotation of the cross flow fan is significantly reduced. Further, since the angles between the two neighboring blades in each group are gradually varied in a minimum manner, the noise level in the low frequency range is greatly lowered. Also, since the blades are arranged in a consistent manner throughout all the blade groups, the vibration produced due to the rotation of the cross flow fan and the noise in the low frequency range are significantly reduced. As a result, the noise and vibration characteristics of the cross flow fan in the whole frequency range are significantly improved.